Low immunoglobulin G concentrations are not associated with an increased risk of peritoneal dialysis-related peritonitis

Background: Peritonitis is a common and severe complication of peritoneal dialysis (PD) and is associated with high morbidity and sometimes also with mortality. Identification of risk factors, as well as protective mechanisms for peritonitis, is important to reduce peritonitis-induced morbidity. According to the current literature, IgG concentrations might be associated with peritonitis in PD-treated patients. In this study, we aimed to investigate possible associations between dialysate or serum IgG concentration and peritonitis risk in a longitudinal cohort of PD-treated patients. Materials and methods: We analyzed prospectively collected data obtained during the first standard peritoneal permeability analysis (SPA), performed in incident PD patients, aged > 18 years who started PD treatment in our tertiary-care university hospital from January 1, 1994 until December 31, 2008. Patients were divided in groups according to dialysate or serum IgG concentrations and according to peritonitis incidence. A possible association between low dialysate or serum IgG concentrations and time to the first peritonitis episode was investigated using cox proportional hazard models. Results: 120 patients were included in our analyses with a median follow-up time of 36 (16 – 92) months. No significant association between dialysate, nor serum IgG and time to peritonitis was found (HR 0.27 (95% CI 0.65 – 1.62), p = 0.911 and HR 0.87 (95% CI 0.70 – 1.68), p = 0.708, respectively). Moreover, IgG concentrations were not associated with peritonitis incidence, nor with the recurrence of peritonitis. Finally, we found no significant difference in dialysate or serum IgG concentrations between patients who remained peritonitis-free (58.0 ± 35.6 mg/L in dialysate, 11.1 ± 4.4 g/L in serum), and those who experienced a peritonitis episode during follow-up (59.5 ± 41.9 mg/L in dialysate, 10.3 ± 4.3 g/L in serum), respectively. Conclusion: Dialysate or serum IgG are not major determinants of local peritoneal defense against peritonitis.